-- http://psoug.org/reference/connectby.html --
CREATE   TABLE t (
rid NUMBER(12),
col1 VARCHAR2(30),
col2 VARCHAR2(300));

INSERT INTO t
   SELECT     id_gen.NEXTVAL, ROUND (DBMS_RANDOM.VALUE (0, 1000), 2),
              ROUND (DBMS_RANDOM.VALUE (0, 1000), 2)
         FROM DUAL
   CONNECT BY LEVEL <= 1000;

COMMIT ;